@CsvSource for inline CSV data in JUnit - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the purpose of the @CsvSource annotation in JUnit?

@CsvSource allows you to provide inline CSV (comma-separated values) data directly in your test method. It helps run the same test multiple times with different inputs easily.

beginner

How do you write multiple test cases using @CsvSource?

List each test case as a string inside @CsvSource, separated by commas. Each string contains comma-separated values representing parameters for one test run.

Example: @CsvSource({"1, 2, 3", "4, 5, 9"}) runs two tests with parameters (1,2,3) and (4,5,9).

intermediate

What happens if the number of parameters in @CsvSource does not match the test method parameters?

The test will fail to run because JUnit cannot map the CSV values to the method parameters correctly. The number of CSV values per line must match the number of method parameters.

intermediate

How can you include a comma inside a value in @CsvSource?

Wrap the value containing a comma in double quotes inside the CSV string. For example: @CsvSource({"\"Hello, World\"", 5}) treats Hello, World as one parameter.

beginner

Show a simple example of a JUnit test method using @CsvSource.

  @ParameterizedTest
  @CsvSource({"2, 3, 5", "4, 5, 9"})
  void testAdd(int a, int b, int expected) {
    assertEquals(expected, a + b);
  }

This runs the test twice with different inputs and checks the sum.

What does @CsvSource provide for a JUnit test?

A Inline CSV data for multiple test runs

B External CSV file loading

C Database connection for tests

D Mocking objects automatically

@CsvSource is used to provide inline CSV data directly in the test code for parameterized tests.

How do you separate multiple test cases inside @CsvSource?

A Using semicolons

B Using commas inside a single string

C Using multiple strings separated by commas

D Using new lines

Each test case is a separate string inside @CsvSource, separated by commas.

If a test method has three parameters, how many values should each CSV line have?

A Three

B One

C Two

D Four

The number of CSV values per line must match the number of method parameters.

How do you include a comma inside a CSV value in @CsvSource?

A Escape with a backslash

B Wrap the value in double quotes

C Use a semicolon instead

D You cannot include commas

Wrap the value in double quotes to include commas inside it.

Which annotation must be used with @CsvSource to run parameterized tests?

A @Test

B @BeforeEach

C @AfterAll

D @ParameterizedTest

@ParameterizedTest tells JUnit to run the test multiple times with different parameters.

Explain how @CsvSource works in JUnit parameterized tests.

Think about how you can run the same test with different inputs easily.

Describe how to format CSV values inside @CsvSource when a value contains a comma.

Remember how CSV files handle commas inside values.